1 INTRODUCTIONOne of the most impor

1 INTRODUCTION
One of the most important applications of GIS is the
display and analysis of data to support the process of
environmental decision-making. A decision can be
defined as a choice between alternatives, where the
alternatives may be different actions, locations,
objects, and the like. For example, one might need to
choose which is the best location for a hazardous
waste facility, or perhaps identify which areas will be
best suited for a new development.
Broadly, decisions can be classified into two
extensive categories – policy decisions and resource
allocation decisions. Resource allocation decisions,
as the name suggests, are concerned with control
over the direct use of resources to achieve a
particular goal. Ultimately, policy decisions have a
similar aim. However, they do so by establishing
legislative instruments that are intended to influence
the resource allocation decisions of others. Thus, for